Dry cleaning method and device

ABSTRACT

An improved dry cleaning apparatus and method for the non-aqueous cleaning of fabric materials comprises the introduction of steam into a dryer chamber containing fabric materials previously washed in a non-aqueous organic cleaning solvent such as perchloroethylene. The steam is heated at a sufficient temperature for a duration of time, both of which are determined by the type of fabric and solvents involved. The heated steam volatilizes any excess cleaning solvent contained in or on said fabric creating a gaseous water/solvent mixture which is then subsequently separated from the fabric materials. The gaseous mixture can be condensed, its component parts separated and re-used in the cycle again.

METHOD OF THE INVENTION

[0001] The invention relates generally to methods for dry cleaningtextiles and clothing. More specifically, the present invention relatesto a dry cleaning apparatus and modifications thereto which removesexcess dry cleaning solvent from the system and is thereby moreenvironmentally friendly.

BACKGROUND OF THE INVENTION

[0002] Dry cleaning of textiles and, in particular, fine clothing is awell known process in which the garment is immersed in a cleaningsolvent other than water which loosens any dirt, grease or grime fromthe fibers of the garment fabric which is then, in one way or another,evaporated off. There are any number of different solvents and methodsfor doing this.

[0003] In conventional dry cleaning systems, the effluent vapors orfumes of the solvent such as perchlorethylene (PERC) emanating from thedry cleaning washing machine and dryers generally are vented directly tothe atmosphere and thus pollute the atmosphere. By being so vented, theyare also lost for reuse. Thus, the escaping vapors not only produce anenvironmental hazard, but their loss is extremely costly to the drycleaning establishment.

[0004] Attempts have been made to remove the solvent vapor contained inthe air-stream through a bed of activated carbon. The carbon absorbs thesolvent vapor or gas held in the air-stream, allowing the thus cleanedair to pass through the carbon bed to atmosphere. See U.S. Pat. Nos.3,203,110 and 3,538,615 to Fuhring et al. Unfortunately, the carbon bedwill only absorb approximately one gallon of solvent per 80 lb. ofcarbon before becoming saturated with solvent vapor, and must then bede-absorbed by passing a “blanket” of steam through the carbon bed in areverse direction to that of the absorption flow. The steam and solventvapors form an azeotrope which must then be condensed, and the resultantwater and liquid solvent must be separated according to their specificgravities. Thereafter, the solvent may then be recycled for reuse.

[0005] U.S. Pat. No. 4,622,039 to Merenda discloses and claims a methodand means to recapture the cleaning solvent and to reuse the same sothat as a result thereof, the solvent is not vented to the atmosphereand thus pollution of the atmosphere is avoided. A dry cleaning washerand a dryer are arranged in a closed cycle system so that the effluentsolvent vapor from the washer is delivered to an accumulator chambersimultaneously with the delivery from the dryer of effluent hot air. Thehot air superheats the solvent vapor thereby increasing its volatilityand the heated and highly volatile solvent vapor is then passed to acondenser which contains feed coils for supplying clean air to thedryer. In passing through the condenser, the superheated solvent vaporinstantly liquifies giving off its heat to the cool air, thuspre-heating the clean air prior to its entry into the dryer. Theliquified solvent is returned to the washer, or to a storage reservoir.

[0006] U.S. Pat. No. 3,951,597 to Mooring discloses and claims a methodof dry cleaning fabrics, draperies or clothing, in situ, by forcefullyinfusing the fabric in the open atmosphere with special fast-acting,versatile dry cleaning solvent so as to dissolve and suspend variousstains and soils in the fabric, even though firmly set due to age.Ambient air is promptly drawn in and droplets of soil-laden solvent ispromptly drawn therethrough by suction into a closed waste and suctionchamber where the soil is deposited in the form of a sludge, while thecarrier air and solvent is discharged to the atmosphere. A special,highly effective, fast-acting, non-flammable and non-toxic solvent suchas methylene chloride, trichloro-ethylene is useful for these purposes.

[0007] U.S. Pat. No. 4,086,705 to Wehr discloses a dry cleaningapparatus wherein petroleum solvent vapors which are discharged from adry cleaning dryer in a heated gaseous mixture of vapors and air arecondensed and recovered, and heat energy is recovered for productive useelsewhere. The gaseous mixture of vapors and air is sprayed withrelatively cool water to condense the solvent vapors. The resultingliquid mixture of water and solvent is withdrawn from the spray chamberand is subjected to gravitational separation. Water reclaimed in theseparation process is reused in the spray chamber. Recovered solvent isreused in a dry cleaning washer. The gravitational separation process ispreferably carried out in a series of gravitational separators, and heatis withdrawn from at least one of the separation units for productiveuse in a heat-consuming device.

[0008] U.S. Pat. No. 3,807,948 to Moore teaches a method of dry cleaningof goods in which the majority of the solvent present in the goods atthe conclusion of the actual cleaning is recovered by circulating air,by means of a fan, through the goods in a dry cleaning drum and througha water-cooled condenser and a heating element. A small remaining amountof solvent is removed from the goods by a deodorizing operation, inwhich air is passed in a closed circuit through the goods in the drycleaning drum and over a refrigerated surface on which the solvent iscondensed.

[0009] Finally, U.S. Pat. No. 3,928,660 to Alderson et al., discloses adry cleaning finishing method and apparatus for use in combination witha steam clothes press for mixing and pressurizing a liquid so that itcan be easily applied to garments being pressed. The apparatus comprisesa supply tank that meters the liquid material into a pressure tank.Steam condensate is mixed with steam from the clothes press and thisprovides the chemically pure water, heat and pressure to the pressuretank that mixes with the sizing concentrate and forces the water-sizingmixture to a spray gun for use when needed or desired by the pressman.

[0010] All of the aforementioned dry cleaning methods either requireconsiderably more steps added to the overall dry cleaning processthereby requiring additional time and expense in carrying out theprocedure or additional pieces of dry cleaning machinery which takes upspace and also adds to the expense of the operation.

[0011] It is an object of the present invention to provide a drycleaning means and method for its operation for removing excess cleaningsolvent from the fabrics cleaned during the dry cleaning process therebyrendering it more environmentally friendly. The removed solvent isrecaptured and contained rather than emitted into the atmosphere.

SUMMARY OF THE INVENTION

[0012] The dry cleaning method and apparatus of the present inventionremoves excess perchlorethylene (PERC) and other volatile cleaningsolvents from clothing and fabric by injecting a predetermined amount ofsteam into a dry cleaning unit or vat wherein the solvent saturatedclothing and fabric have been treated. The hot steam further volatilizesany additional PERC remaining in or on the fabric and this is removedfrom the container by vacuum. The PERC/steam mixture is then condensedand the two components separated for re-use.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is an over-all schematic side view of a standard drycleaning dryer with the attached PERC steam stripper of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0014] During the course of the dry cleaning cycle in any standard drycleaning system, the volatile cleaning solvents such asperchloroethylene (PERC) will often become absorbed into certain fabricsor clothing articles in excess amounts. Dense fabrics such as camel hairor wool often pose a problem in this regard. In many of the dry cleaningprocesses known in the art, the PERC cleaning solvent is not alwaysfully removed and thus can result in an unpleasant odor or feel when thearticle of clothing is worn.

[0015] The present apparatus and method insures that all of the cleaningsolvent used in the dry cleaning process is removed from all thearticles of clothing without damaging even the most sensitive offabrics. This is achieved by injecting a pre-determined amount of steaminto the drying vat or unit for a precisely defined period of time basedupon the size of the load and the types of fabric being cleaned. Thesteam insures that any excess PERC remaining in the fabric being cleanedis removed by volatilizing the solvent molecules and then physicallyseparating them from the fabric altogether. This not only results in adry cleaned fabric material that is free from any undesirable chemicalodor and slippery feel, but the perchloroethylene or other cleaningsolvent can be separated, collected and condensed for re-use.

[0016] Referring now to FIG. 1, a conventional dry-cleaning dryer (2) orvat is utilized to tumble dry the clothing articles and fabrics (notshown) that have been pre-treated with and are saturated with thecleaning solvent of choice, generally perchloroethylene (PERC). Thevolatile cleaning solvents for the most part are driven off the fabricthrough the application of heat at the pre-determined range and durationaccording to the types of fabric being cleaned.

[0017] In the present invention as disclosed in FIG. 1, a steam sourcefor the dryer is provided by the means of a steam pipe (4) locatedproximate to the dryer and is in communication therewith by means of asecondary conduct or pipe (6). A plurality of secondary conduits (notshown) could also feed off the same steam pipe (4) enabling several drycleaning dryers to be utilized in tandem all at once. The steam itselfis produced by a boiler either located on the premises or distallythereto and is fed via piping to the primary steam pipe (4).

[0018] As discussed earlier, the amount of steam injected in the dryerand the amount of time during which this occurs depends on the size ofthe dry cleaning load and the types of fabric being cleaned. Thetemperature of the steam injected is generally governed by these factorsand the type of solvent used. Obviously, the smaller or lighter the loadand/or the more delicate the fabric, the shorter the duration of steaminjection and stripping and/or the cooler the temperature.

[0019] The duration of steam injection then is controlled by the use ofa timer (8) located externally to the dry cleaning dryer or vat (2).Preferably, the timer is in juxtaposition to or attached to the outercasing or wall of the dryer (2) and can be manually set or adjustedtherefrom. The timer (8) is in electrical communication (10) with thesolenoid valve (12) which it operationally controls. Hence, when thetimer is turned on to a specified duration of time, the solenoid valve(12) is turned to its open position and the hot steam from the steampipe (4) is released and enters into tumble dryer (2). The steam entersinto the dryer chamber (2) and over time fills the space not taken up bythe fabric or clothes. As the clothes tumble about within the dryer (2),the hot steam thoroughly contacts the surface of the clothes andvolatilizes or evaporates and cleaning solvent residue remainingthereon. Once the predetermined duration of solvent stripping hasconcluded, the timer (8) turns off thereby shutting the solenoid valve(12) and cutting off the flow of steam into the tumble dryer or vat (2).

[0020] The dryer (2) is also provided with a conventional exhaust fan orvacuum (not shown) which collectively draws the steam and volatilizedcleaning solvent out of internal chamber of the dryer (2) wherein it issubsequently cooled, condensed and collected. The two liquids can thenbe either physically separated or separated by distillation means as isknown in the art. In this manner, the perchloroethylene (PERC) or otherorganic cleaning solvent as well as the water if necessary can bere-used thereby adding a cost saving benefit to the process. This isalso ecologically sound in that the solvent is self contained and nothazardously discharged into the external environment.

[0021] Referring again to FIG. 1, the solvent steam stripper apparatusof the present invention can alternatively be comprised of a manual shutoff valve (14) for the shut off and/or open control of the steam releaseinto the internal chamber of the dry cleaning dryer (2). This manualcontrol valve can either be substituted for or utilized in conjunctionwith the electronically controlled solenoid valve (12) and timer (8)combination. If the manual shut off valve is used in the system byitself, it should only be used when the fabrics to be cleaned andsteamed stripped are not delicate materials thereby requiring the use ofprecise steam injection periods and wherein these times can beoperatively determined by the dry cleaner personnel themselves. Whenused on the secondary injection pipe (6) together or in tandem with theelectronically controlled solenoid valve (12) and timer (8), the manualvalve (14) can be utilized as an emergency shut off means or whenappropriate, in lieu of the solenoid valve (12) and timer.

[0022] As discussed earlier, the temperature of the steam injected intothe dryer or vat (2) and the duration of time during which the steamcontacts the clothes and strips the fabric of excess cleaning solvent isgenerally dependent upon the type of fabric being cleaned and, to alesser degree, the type of solvent used. The more delicate the fabric,shorter steam stripping times and cooler steam temperatures provide thebest cleaning results. Consequently, the more durable fabrics cangenerally withstand higher steam temperatures and longer steam strippingapplication times. And generally speaking, the duration of time duringwhich the steam is allowed to contact the clothes is inversely relatedto the temperature of the steam. The hotter the steam, the shorter thesteam/clothing contact period and vice versa.

What I claim is: 1) A method for the cleaning of fabric wherein a non-aqueous organic cleaning solvent is used to clean said fabric further comprising the application of steam to said fabric during the drying cycle. 2) The method of claim 1 wherein said steam contacts said fabric at a temperature and for a period of time sufficient to remove any excess organic cleaning solvent embedded in or on said fabric materials. 3) The method of claim 2 wherein said steam volatilizes said organic cleaning solvent thereby forming a gaseous water/solvent mixture which is subsequently drawn away and separated from said fabric. 4) The method of claim 3 wherein said gaseous water/solvent mixture that has been separated from said fabric is cooled, condensed and further separated into water and solvent fractions. 5) The method of claim 4 wherein said cleaning solvent is perchloroethylene. 6) An improved dry cleaning apparatus for the non-aqueous cleaning of fabric materials comprising: a) an internal drying chamber; b) a steam source; c) a conduit for the introduction of said steam into said drying chamber; and d) an exit means for the removal of said steam from said drying chamber. 7) The improved dry cleaning apparatus of claim 6 wherein said drying chamber is of sufficient size so as to contain a plurality of said fabric materials which have been contacted with a sufficient amount of non-aqueous, organic cleaning solvent prior to said fabric's introduction into said chamber. 8) The improved dry cleaning apparatus of claim 7 wherein said chamber conduit introduces said steam at a suitable temperature and for a time sufficient to volatilize any excess organic cleaning solvent remaining in or on said fabric materials resulting in a gaseous water/solvent mixture that becomes separate and apart from said fabric material. 9) The improved dry cleaning apparatus of claim 8 wherein said conduit further comprises a valve for the control of the release and stoppage of the introduction of said steam into said drying chamber. 10) The improved dry cleaning apparatus of claim 9 wherein said valve is a solenoid valve operatively connected to a timer device for the selective durational control of the introduction of said steam into said drying chamber. 11) The improved dry cleaning apparatus of claim 10 wherein said timer device is electronically connected to said solenoid valve for the selective durational control of the introduction of said steam into said drying chamber. 12) The improved dry cleaning apparatus of claim 9 wherein said valve is manually operated. 13) The improved dry cleaning apparatus of claim 11 further comprising a manually operated shut off valve. 14) The improved dry cleaning apparatus of claim 13 wherein said exit means comprises a second conduit in communication with said dryer chamber operatively connected to an exhaust or vacuum fan. 15) The improved dry cleaning apparatus of claim 14 wherein said exhaust or vacuum fan draws said water/organic solvent mixture from said drying chamber and deposits it in a secondary chamber wherein it is cooled and condensed. 16) The improved dry cleaning apparatus of claim 15 wherein said water/organic mixture is separated after condensation into its two component parts for re-use. 17) The improved dry cleaning apparatus of claim 16 wherein said fabric materials are clothes, linens, sheets, blankets, rugs, carpets, draperies, coats and mixtures thereof. 